RS- Phisiology
What happens when atmospheric pressure exceeds intrapulmonary pressure (in the lungs)?
air flows into the lungs
What happens when intrapulmonary pressure exceeds atmospheric pressure (in the lungs)?
air flows out of the lungs
What are pressure changes driven by?
the volume in the lungs
what does an increased volume do?
decrease intrapulmonary pressure
what does decreased volume do?
increases pulmonary pressure
What happens to the diaphragm during inspiration?
it contracts and moves downward and the external intercostals contract which lifts ribs upward and laterally
What is the net result of inspiration?
increase in the volume in the thoracic cavity and a decrease in pressure
What other muscles does maximal inspiration use?
Pectoralis minor, sternocleiomastoid, scalenes
What kind of process is expiration?
passive
what happens during expiration to the diaphragm, lungs and muscles
the diaphragm and external muscles relax and the lungs recoil (contract/get smaller)
What is the result of expiration?
decrese in volume of the thoracic cavity and an increase in pressure
What muscles allow for forced expiration?
internal intercostals and abdominal wall muscle
What areas do gases diffuse from?
areas of high pressure to areas of low pressure
Partial pressure
amount of pressure exerted by each gas which each account for a portion of the total pressure in the air
What is the atmospheric pressure at sea level?
740 mm Hg
PO2
partial pressure
mm Hg
Millimeters (mm) of mercury (Hg)
Equation for finding the partial pressure
Atmospheric pressure * oxygen (0.21) = partial pressure
What is the percentage of oxygen in the air?
21% or 0.21
When causes the O2 to diffuse into the capillary?
when the partial pressure of O2 is higher in the Alveolar air than in the capillary air
When does Co2 diffuse out of the capillary?
when the partial pressure of the CO2 is higher in the blood than in the Alveolar air
How is O2 transported
98% of oxygen is carried bound to the hemoglobin in RBCs, (oxyhemoglobin), then each Hb binds 402 molecules 4 polypeptides, each with one iron atom
What does CO2 do to our cells
causes them to become acidic and for PH level to go down
How is 7% of Co2 transported?
dissolves in blood
How is 23% of Co2 transported?
it bonds to hemoglobin (creates carbaminohemoglobin)
How is 70% of Co2 transported?
in the form of bicarbonate atoms
Co2 bicarbonate atoms
Co2+H2O=H2Co2= H+HCO3, they then diffuse into the blood plasma and H+ binds to HB and temporarily acts as a buffer